Changes in the Activities of Lysosomal Enzymes in the Fat Body and Midgut of Two Lepidopteran Insects (mamestra Brassicae and Pieris Brassicae) During Metamorphosis

1.1. The activities of three lysosomal enzymes (acid phosphatase, β-galactosidase, catepsin D) was observed during metamorphosis in the fat body and midgut cells of two insects (Mamestra brassicae and Pieris brassicae).2.2. The activities increased slightly during the feeding period and showed a sharp rise at the beginning of the wandering period.3.3. Subsequently, a decrease was observed during the pre-pupal stage and pupation.4.4. The activities increased again 2 days after the larval-pupal moult.5.5. We suggest that an inhibitory mechanism works in the studied cells before pupation to protect the stored proteins from the degradation until the beginning of differentiation of imaginai cells in the pupal stage.